Cleaning compositions nowadays come in a number of product forms, such as granules, liquids and unit dose forms, including water-soluble or water-permeable pouches.
The most common process for making water-soluble pouches with products such as cleaning products is the so-called vertical filling process. Hereby, a vertically hanging string of open pouches is formed by folding a film, which is then transported in under a filling machine which partially fills the pouches, allowing a head space whereby the top part of the open pouch is then subsequently sealed together to close the pouch. The typically pillow shapes pouches are then cut loose of the string to form individual pouches.
A second known process for making pouches is by use of a die having series of moulds and forming from a film, open pouches in these moulds, which can then be filled and sealed. This method uses the pouch film material more efficiently and the process has a more flexibility in types of pouch shapes and ingredients used, however, the process is not very suitable in industrial, because it can not produce large quantities of pouches (per time unit), in an easy and efficient manner.
A third process proposed is the formation of pouches in moulds present on the surface of a circular drum. Hereby, a film is circulated over the drum and pockets are formed, which pass under a filling machine to fill the open pockets. The filling and sealing needs to take place at the highest point (top) of the circle described by the drum, e.g. typically, filling is done just before the rotating drum starts the downwards circular motion, and sealing just after the drum starts its downwards motion.
The problem associated with the vertical filling machine is that the process is not very efficient: the process is intermittent and very slow, for example due to process speed changes from one step to the next step, and each pouch formation step result typically only in one string of pouches in one dimension; thus, only a limited amount of pouches per minute can be formed. Moreover, the large quantities of film are used per product dose, because the method does not allow complete filling of the pouches and the method does not allow stretching of the film. Also, there is not much flexibility in shapes of pouches formed.
The problems associated with the second process using a die with moulds include also that that process is intermittent (or an index process), and that the process is slow and involves acceleration and deceleration, which reduces the overall speed and moreover, causes product spillage out of the open pouches. Also, the output of this process is not very high (per time unit).
The circular drum process overcomes some of the disadvantages of the first vertical filing process (and even the second (moulding) process to a certain extend), because it does not need speed changes (no acceleration/deceleration) and it can more easily provide pouches in two dimensions and the shape of the pouches can be changes to some extend. However, the spillage from the pouches is quite substantial, due to the circular movement, which causes product to spill onto the sealing area, and this causes problems with the sealing (leaking seals). Also, the process does not allow the pouches to be filled completely, because the spillage is then even more of a problem. Also, this process has even more significant problems when used for liquid products, which are more likely to cause large spillage, due to the circular motion. Moreover, the filling and sealing has to be done around the highest point of the circle movement of the drum, and thus hugely reducing the overall speed and the output of the pouch formation process.
Thus, alternative ways and more efficient ways to produce unit dose products are desirable.
The inventors have now found an improved process for making water-reactive or water-soluble pouches in industry. They found a way to overcome the problems of an intermittent process. Also, they found a way to overcome the problems of processes using a drum or the vertical filling technique.
The invention provided is a horizontal, continuous process whereby a horizontally positioned portion of an endless surface with moulds (in two dimensions), which moves continuously in one direction, is used to form the pouches, namely whereby a film is continuously fed onto this surface, and then, the film is drawn into the moulds on the horizontal portion of the surface, to continuously form a web of open pouches positioned in horizontal position, which can then be filled with the product (such as cleaning products, including liquid product), whilst horizontal and whilst moving continuously, and which is then preferably also closed whilst still horizontal and moving continuously. Hereby, the pouches can be filled about completely, because no speed changes occur and thus much less or no spillage. Also, the process allows great flexibility in film size used, pouch sizes, pouches shapes, product forms, time required per step (by varying length of horizontal surface, or changing the constant speed, for example) without impacting much on the overall output of the pouch making process. Also, the process uses a minimum of film material per pouch, in particular if during the pouch formation step or closing step, the film is stretched.